Process for the manufacture of vinyl trichlorosilane

ABSTRACT

IMPROVED PROCESS FOR PRODUCING VINYL TRICHLOROSILANTE BY REACTING VINYL CHLORIDE AND TRICHLOROSILANE UNDER SUBSTANTIALLY ANHYDROUS CONDITIONS AT ABOUT 680 TO 850*C. USING A RESIDENCE TIME OF ABOUT 0.2 TO 1.8 SECONDS.

United States Patent 3,706,776 Patented Dec. 19, 1972 In accord with andfulfilling these objects, one aspect 3,706,776 of this invention lies inan improved process of producing rnocE s s go ng t OF vinyltrichlorosilane by reacting vinyl chloride and tri- Claus-DietrichSeiler, Rheinfelden, Hans-Joachim Vahlen- 5 f gi g gg i 5 3? gg g giggfgi i zfi gfig i gggg Sieck wehr and Kurt Boje Rheinfelden Germany tem forresidence times of about 0 2 to 1-8 seconds It assignors to DynamitNobel Aktiengesellschaft, Troisdorf, Germany is preferred to carry outthe reaction at about 700 to No Drawing. Filed Jan. 6, 1971, Ser. No.104,523 730 C. for a contact, or residence tlme of preferably 1 Claimspriority, application Germany, Jan. 20, 1970, to 1.6 seconds.

P 20 02 258.6 It will be noted that these conditions of reaction areC07f 7/14 substantially contrary to the reaction parameters defined US.Cl. 260-4482 E 4 Claims in the prior art It has been found that, if theabove conditionsare met, the yields increase greatly in comparison toyields ob: ABSTRACT OF THE DISCLOSURE tained within the known processparameters and the for- Improved process for producing vinyltrichlorosilane by mation of by-products is greatly suppressed. Thespecial reacting vinyl chloride and trichlorosilane undersubstanadvantage of the new process, namely the application of tiallyanhydrous conditions at about 680 to 850 C. using higher temperatures,shorter detention times and anhya residence time of about 0.2 to 1.8seconds. drous conditions, consists in the fact that the danger ofcoking present because of the use of longer residence or contact timesis substantially completely eliminated and This invention relates to theproduction of vinyl trisubstantially higher yields of vinyltrichlorosilane are chlorosilane. It more particularly refers to anovel, imobtained. proved process for producing this compound. Thereaction is preferably performed at normal, at-

It is in the prior art to manufacture vinyl trichloromospheric pressure.A small overpressure of up to 2 at silane by reacting trichlorosilanewith acetylene or by mospheres gauge pressure or a small vacuum will notreacting trichlorosilane with vinyl chloride in the gas particularlyaffect the conversion and/or the yield. phase. Since the proc u e usingacetylene necessitates The reactants are preferably fed to the processin batch relatively great expenditure on safety measures, this procorcontinuous manner in stoichiometric quantities. Any e53 has not acquiredeXtenSiVe industrial 1186- excess of one or the other of the reactantsis reasonable More suitable for industrial application is the processprovided such excess if any is Within economical limits.

of reacting trichlorosilane with vinyl chloride in the gas As alreadystated, the reaction is carried out under sub- P If a mixture of Vinylchloride and hydrogen chiOrO- stantially anhydrous conditions. If thevinyl chloride resilanes is passed through ceramic or metal tubes attemperet nt i moi t, it should be dried prior to being fed to atllles 0f0 t0 and detention times greater than the reaction, to the lowestpossible moisture content for 2 seconds, preferably 5 to 20 seconds,there are produced the achievement of high yields. a mixture of vinylchlorosilanes. Where trichlorosilane is Th ti i performed preferably intubular reacused as the hydrogen chlorosilane, its reaction With vinyltors. Suitable reactor materials are metals, especially those chlorideunder the conditions set forth above, a yield of hi h cause nodecomposition or transposition of the only 53 mole-Percent is achieved,With reference to the starting products and end product, such as iron,ceramic, Vinyl Chloride reactant, which is the reactant used in agraphite and other such materials, substantially inert masioichinnleiricdeficiencyterials may also be used for the reactor.

The ratio f h reactants to ne h r is i in the The vinyl trichlorosilanemanufactured according to the Prior art to be of no particularimportance insofar 38 yield invention is a valuable product which isused in dressing data are concerned. According to the prior art,practical materials containing silicates.

Y that is yiel s up to the 53% stated above h The process of the presentinvention is illustrated by not been achieved at reaction temperaturesabove 650 C. h f ll i examples:

The prior art has laid the blame for these less than spectacular yieldsupon an alleged great decomposition EXAMPLES la TO 2a as well astranspositions resulting in undesired by-prod- 5O ucts such as silicontetrachloride and methyl trichloroy Vinyl chloride and trichlorosilanewere first mixed il together in quantity ratios listed in the tablebelow, and

It is an object of this invention to provide an improved preheated toabout they Were h n introduced process for roducing inyl t ichlorosilanginto an iron pipe 150 cm. long Wlth an lI'lSlde diameter It is anotherobject of this invention to provide such an 55 0f 35 at variousVelocities, and heated to t improved process which gives greater yieldsof the desired Peratures Stated in the table- The PwdlltitS emerglngfrom product than the prior art. the reaction tube were cooled andcondensed. The con- Other and additional objects of this invention willbedensate obtained was tested qualitatively and quantitativecomeapparent from a consideration of this entire specifily by distillationand gas chromatography. The results cation and the claims includedhereof. obtained are also shown in the table.

TABLE Input of starting materials Transforma- Trichloro- Yield of vinylAverage tion to vinyl silane trichlorosilane Trichloro- VinyldetentionTempertrichlororecovery as percent of silane chloride time ature silane(in (in mole the reacted (in moles) (in moles) (in sec.) (inC.) molepercent) percent) trichlorosilane 145 17s 1. 650 49 45 88. 0 145 176 1.75 720 69 19 85. 2 145 176 1. 75 750 59 19 72. 9 186 22s 1. as 650 39 5s92. 9 186 I 228 1.35 720 13 as 186 22s 1. 35 750 74 1s 87. 1

What is claimed is:

1. In the process for the manufacture of vinyl trichlorosilane byreacting trichlorosilane and vinyl chloride at elevated temperature; theimprovement which comprises carrying out the reaction undersubstantially anhydrous conditions at a temperature of 680 to 850 C.,and an average contact time of 0.2 to 1.8 seconds.

2. Improved process claimed in claim 1, wherein the reaction is carriedout in a tubular reaction zone of iron, ceramic, or graphite.

3. Improved process claimed in claim 1, wherein the reactiontemperatureis about 700 to 730 C. and wherein the average contact time is 1.0 to1.6 seconds.

' 4. Improved process claimed in claim 1 wherein the reactiontemperature is about 700 to 730 C.

References Cited JAMES E. POER, Primary Examiner 10 P. F. SHAVER,Assistant Examiner U.S. C1. X.R.

